flyeyes

flyeyes

Well Known Member
Thought I'd post this for those of us who do our own oil changes, but haven't seen a problem yet.

This filter was off of our IO-550 after a mag failure which resulted in advanced timing and detonation in a cylinder.

The engine came off and went back to TCM.

You can see the small chunks of metal everywhere, mostly non-magnetic
http://img87.imageshack.us/img87/4904/metalinfilteral2.jpg
 
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Which mag type?

Hi.

Thanks for the pics and story. Glad everything went well with the people onboard!

What kind of mags where on the plane? (just courious)
 
So, do you think the mag failure and resulting detonation lead to what we see in the filter? Or is all the filter contamination simply coincidental with the mag problem?
 
ao.frog said:
Hi.

(snip)

What kind of mags where on the plane? (just courious)
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They were stock "Continental" mags, which are really just relabeled Bendix mags. They came new on the certified IO-550.

The problem occurred at about 600 total time in service. about 100 hours earlier, both mags were inspected in accordance withe the SB recommending 500 hour inspections.

Fortunately, all of our paperwork was squeaky clean, we had carefully documented every bit of required and recommended maintenance, and we had two weeks of TCM "Platinum" warranty left.

TCM has an analytical lab which went through the engine and especially the mag. They sort of implied that it we had used aftermarket parts for the SB we'd be on out own, but fortunately we had used OEM parts and had all the paperwork.
 
Bill Wightman said:
So, do you think the mag failure and resulting detonation lead to what we see in the filter? Or is all the filter contamination simply coincidental with the mag problem?
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No question at all.

This was the sixth leg the airplane had flown that week, everything including oil levels and mag checks had been normal.

First indication was a sudden CHT redline on one cylinder which didn't respond to a power reduction and mixture going full rich. Less than a minute later the same CHT went offscale low.

This happened in cruise at a relatively low power setting, and the two (very experienced) pilots on board both thought that it was the CHT probe. They discussed whether the six-cylinder continental was running rough but decided it was probably not. As they reduced power for descent they changed their minds, and the FBO called them to tell them the airplane was smoking badly in the pattern. After shutdown, the oil level was at 3 quarts.

We pulled the plugs and borescoped the #3 cylinder--it looked like someone had been beating on it with a ball-peen hammer and half of the exhaust valve was missing.

We didn't go any further since TCM threatened us with loss of warranty coverage if we did any more disassembly or troubleshooting. We just pulled the motor and trucked it to Mobile.
 
Could you describe the mechanics of the mag failure?

Boy, I hope I never see an oil filter like that one!
 
DanH said:
Could you describe the mechanics of the mag failure?

Boy, I hope I never see an oil filter like that one!
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From a phone conversation with the tech rep:

He said that the plastic gear had lost a bunch of teeth (32 IIRC). They attributed this to embrittlement because the mag wasn't venting properly. The missing teeth caused the timing to "jump around randomly."

I asked why one cylinder was destroyed and the others looked OK on a quick borescope. He answered that it was a common finding with detonation, and the margins vary among cylinders.

He also said that on teardown all six cylinders showed damage, and even the case studs were "pulled." I kind of suspect that they just disassembled the motor and moved our data plate over to a reman. The engine we got back had the same data plate, but was otherwise basically a reman (new pistons/jugs, new case, reman'd crank).
 
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James, Thanks for airing this on VAF. Superb job all around, from the event itself, even to dealing with TCM who apparently didn't want to cover this one if at all possible.

Hope your new engine does much better!!

Rgds,

Bill
 
Bill Wightman said:
Hope your new engine does much better!!

Rgds,

Bill
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That's a whole other story ;-)

I will say that I couldn't be happier with the warranty service the second time.

The remanufactured crank they sent us cracked at about 91 hours in service. When we sent pictures, they literally shipped a new engine the next day. Our total downtime from grounding the airplane to flying with the new motor was one week.

The engine currently in the airplane is a jewel. It runs even smoother than the original one, and has had absolutely zero squawks from day one.
 
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